The 1989 Loma Prieta earthquake revealed structural deficiencies in the eastern span of the San Francisco-Oakland Bay Bridge, and within a few years, then-Gov. Pete Wilson’s administration proposed a $1.4 billion replacement viaduct.

When the replacement opened two decades later, however, it had mushroomed into a $6.4 billion single-tower suspension span, plagued by reports, mostly in The Sacramento Bee, of long delays, cost overruns and construction deficiencies that were ignored or covered up.

This week, Senate Transportation and Housing Committee Chairman Mark DeSaulnier released an investigative report about the mismanagement.

It confirmed suspicions that the debacle is rooted in political hubris, including pressure from two mayors, San Francisco’s Willie Brown and Oakland’s Jerry Brown, and other politicians for route changes and redesigns to make the new section an artistic spectacle.

Not only did the radical design that resulted from political interference raise costs and add years of delay, but its complexity led to construction defects and alleged cover-ups.

“To be sure, some of the longest delays were not the fault of the bridge builders,” says the report. “Rather, they were the product of political infighting at the very highest levels of California state government.”

Nor is the Bay Bridge the only example of political ego-tripping.

When Sacramento International Airport needed to replace one of its outmoded terminals, the airlines suggested duplicating a handsome terminal nearby that had already proved its workability.

However, the now-retired airport manager, Hardy Acree, persuaded county supervisors in 2006 to build a grandiose terminal costing a billion dollars, and raising fees on airlines and passengers to pay for it.

“We didn’t want to stand in the shadow of another city,” Acree was to say later.

Since 2006, the airport’s passenger traffic has declined by nearly 20 percent, and paying for the terminal has become problematic.

And then there’s Orange County’s project to convert a former military air base into a world-class “Great Park” that has turned out to be anything but great.

The city of Irvine has spent $200 million on the project but has almost nothing to show for it. And a new audit lays the onus on a city councilman and former mayor, Larry Agran, who became its virtual czar.

Agran – who once ran for president – passed out no-bid contracts, often to his friends and political associates, the audit said. One political management firm close to Agran received a $100,000-per-month public relations contract.

Political ego triumphed over common sense and the public interest in all three projects. It’s something to keep in mind as Jerry Brown trumpets a bullet train and twin water tunnels, which together would cost at least $100 billion.